IPv6, The IP-Address Solution: What It Is, and Why It Matters

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If there’s one set of letters that’s on an unstoppable march, it has to be “I” and “P,” which, when partnered as “Internet protocol,” are the juice of a worldwide network, and a zillion offshoots. There’s IPTV, voice-over-IP, TCP/IP, and on and on.

IP, simply put, is the essence of the Internet, public and private.

(As this column has noted before, “IP” is also one of those acronyms that isn’t all that graceful when spoken. Try this out loud: “It seems like IP everywhere.”)


Lately, a problem is lurking in IP. It’s fairly big, data technologists say, but it’s not insurmountable. The problem is this: A shortage is potentially in the works, if something corrective isn’t done soon.

Specifically, it’s a shortage of IP addresses. Right now, outside of a fix known as IPv6, it looks like there won’t be enough addresses to service all of the gizmos that need, or will need, an IP connection. The shortage could get ugly, and it could get ugly within two years.

Consider: By 2007, as many as 10 things in your house could require an IP address to function properly. In some cases, one device may need two, or even three, IP addresses.

The count goes like this: There’s your cable (or digital subscriber line) modem. Maybe you have more than one. Then there’s your voice box, known industrially as an “E-MTA,” for embedded multimedia-terminal adapter. It gets two IP addresses: One for the voice side, one for the data side. That’s four.

It’s entirely possible that your digital set-top contains an embedded cable modem, known industrially as “DSG,” for “DOCSIS [Data Over Cable Service Interface Specification] set-top gateway.” Maybe you have two of those. That’s six.

Then there’s the stuff that’s coming, especially from the consumer electronics world. Starting in a few months, high-end televisions and HDTV/DVR combinations will start entering the retail marketplace, that are tagged as some variation of “interactive digital cable ready.”

The “interactive” part means they are two-way, which means they contain both an embedded DSG modem, and a CableCARD slot. Both get IP addresses. So if you buy one, that’s two more IP addresses somebody (your service provider) needs to score for you.

We’re up to eight. Start thinking about Web cams, game players and other in-home peripherals, and it doesn’t take too much extra imagination to run up to 10 things. Maybe more. And they all need their own IP address.

And that’s just your house. Imagine for a second that you’re Comcast Corp. If each home within its service footprint contains 10 things that need IP addresses, that means access to something like 100 million IP addresses.

That’s about 40 million more IP addresses than Comcast can get its hands on, right now, using current technology.


Happily, relief is on the way, and it’s the subject of this week’s translation: IPv6, also known as the “next generation” of IP. It goes like this: Right now, the Internet — all of it, public and private — runs on IPv4. IPv6 is the next version of it.

IPv6 contains a lot of features, but the big one for broadband service providers is its massive expansion of IP addresses. The numbers get big fast, but here’s some context: With IPv4 — what we’re all using now, even though most of us don’t know it or care — something like 4 billion total IP addresses are available for global circulation.

With IPv6, the number of available IP addresses is a one with 18 zeros behind it — which is roughly analogous to the number of known stars in our universe. In short, we should be OK for a long while, with IPv6.

The addresses themselves are longer, too: Four times longer, stretching to 128 bits, from 32 bits. In the data world, it is a huge, huge increase in address space.


As industrial efforts go, the transition to IPv6 is a component of the CableLabs effort known as DOCSIS 3.0. That’s the same one that will offer “channel bonding,” and a laundry list of other features.

MSO data technologists are already keenly focused on the IPv6 transition, saying that it will begin in backbone networks before it shifts into cable’s core infrastructure, and, especially, the cable-modem termination system, or CMTS. In the early phases, the work will be conducted in the background, as a means to manage and operate existing gear.

The last step, as with most big network changes, will occur in the home — meaning that future cable modems and IP-capable devices will be outfitted to understand how to operate with the longer (128-bit) addresses that come with IPv6. It also bears noting that computer operating systems, like Microsoft Windows, will be outfitted to handle IPv6, perhaps as early as next year.

All along the way from IPv4 to IPv6, involved networks and technologies will need to support “dual stacks,” meaning, software that can interpret both versions. Right now, that puts the development onus on makers of CMTS gear. Moving from 32-bit to 128-bit addressing, as Arris Group Inc. technologist Rick Arnold describes it, is “a non-zero effort.”

That’s tech-speak for “it’s going to be hard.”

At the consumer level, none of this really matters. It’s plumbing, to be sure, but it’s plumbing that matters, because it’s needed for scale. From the sounds of the people working on it, though, the resounding sentiment is this: Start now or be sorry later.